Cellular communication systems continue to grow in popularity and have become an integral part of both personal and business communications. Cellular telephones allow users to place and receive phone calls most anywhere they travel. Moreover, as cellular telephone technology is increased, so too has the functionality of cellular devices. For example, many cellular devices now incorporate Personal Digital Assistant (PDA) features such as calendars, address books, task lists, calculators, memo and writing programs, etc. These multi-function devices usually allow users to wirelessly send and receive electronic mail (email) messages and access the internet via a cellular network and/or a wireless local area network (WLAN), for example.
As the functionality of cellular communications devices continues to increase, so too does demand for smaller devices that are easier and more convenient for users to carry. As any circuit boards and electronic components thereon are reduced in size and placed closer together, including antenna and microphone components, and associated software requirements change, development costs increase. As a result, any testing of minor circuit, antenna and software changes becomes increasingly important since these minor changes can affect overall device performance, for example, the total radiated power (TRP) emitted from the device.
During the development stage of such mobile wireless communications devices, changes are made in circuit design, manufacturing specifications, antenna design, software and other modifications, affecting the TRP emitted from the device. Thus, with each modification, the device is tested to determine how the modifications affect the TRP. The measurement time for TRP in such devices typically takes about two hours across four frequency bands, for example, the 850, 900, 1800 and 1900 MHz bands. Testing also occurs in three channels for each frequency band corresponding to the low, middle and high channels. These measurements slow down the design and development of the device since testing occurs to meet system specifications such as the TRP, harmonics and similar details. Typically, TRP measurements occur in a large anechoic chamber using expensive test equipment such as a spectrum analyzer. The device to be tested is moved from the development laboratory to the anechoic chamber, which in itself takes time. The device is supported by a turntable or similar support and rotated 360 degrees horizontally and vertically to measure the total radiated power in an isotropic pattern. This is also time consuming and labor intensive, taking another two hours minimum.
With each change in device design during the development stage, multiple measurements are taken in this expensive anechoic chamber, not only tying up an expensive anechoic chamber every time a measurement is taken, but also requiring the device to be moved to the anechoic chamber from a development lab. As a result, the entire development of the device is slowed down appreciably. A better development system for measuring TRP of mobile wireless communications devices is required without making multiple measurements in an expensive anechoic chamber as is accomplished currently using prior art systems.